The first of about two dozen trucks carrying parts to assemble a drilling rig pulled into the Bayou Corne community around 11 a.m. Wednesday, Assumption Parish Sheriff Mike Waguespack said.
They rig will be put to work drilling an observation well to search for a possible connection between a closed well on the property of Texas Brine Co. of Houston and a sinkhole that developed earlier this month near La. 70 and Bayou Corne.
Texas Brine spokesman Sonny Cranch said the first 10 tractor-trailers carrying rig components bound for the site of the 2.5-acre sinkhole adjacent to the Napoleonville Salt Dome arrived on schedule in Assumption Parish. The rest were to arrive Thursday.
Once the rig is assembled, Texas Brine officials expect the well to be completed in about 40 days. The rig, which will stand 140 feet high, will be assembled on a well pad about 900 to 1,000 feet from the sinkhole, Cranch said.
The Louisiana Department of Natural Resources ordered Texas Brine last week to drill the well to see whether one of its salt dome caverns may have failed and caused the sinkhole.
DNR officials have said they suspect Texas Brine’s cavern may have been carved too close to the Napoleonville Dome’s outer rim, causing the sinkhole to form Aug. 3 and swallow up forested swamps on Texas Brine property.
The company also is working to install instruments that will measure ground movement surrounding the sinkhole, Cranch said, and he expects that work to be completed within a couple of days.
Company officials are working with state and parish officials to establish an evacuee fund, Cranch said, adding the company has received a list of residents affected by the evacuation order.
The sinkhole is now 476 feet by 640 feet; the natural growth of the sinkhole was expected and could continue.
Officials monitoring the sinkhole via regular flyovers reported the change in size Wednesday, but said it is still much smaller than the maximum projected size that scientists said it could grow.
“Hopefully, we’ll have this (rig) completed by late Friday or Saturday,” Cranch said. “They’re going to work 24 hours a day to assemble the rig. As soon as they get the rig completed, they’re going to start driving their casings.”
DNR personnel are referring to the well as an “observation well,” Cranch said, rather than a relief well because officials “don’t know if it’s going to relieve anything.”
“If there’s any buildup of natural gas, this would be a conduit to relieve the pressure,” he said. “That’s not expected. It will, however, will be used as a conduit to insert imaging equipment to see if (the sinkhole is) related to the cavern.”
The Governor’s Office of Homeland Security and Emergency Preparedness also hosted a unified command meeting Wednesday to ensure the response is coordinated, the agency reported, adding the organization compiled an updated situational summary for the parish and posted it online at http://gohsep.la.gov.
The state Department of Environmental Quality is conducting air-monitoring tests by boat where natural gas is bubbling to the surface of Bayou Corne, collecting air samples in the Bayou Corne community and deploying its Mobile Air Monitoring Lab for air-quality monitoring and sampling in the area. To date, none of the samples showed any health threats related to air pollution.
In addition to DEQ’s analysis, the state Department of Health and Hospitals has been analyzing environmental samples from DEQ. DHH’s environmental epidemiology staff has not detected a health threat.
Meanwhile, DNR officials continue to ensure that Texas Brine conducts its drilling well operations in accordance with its emergency order.
State Department of Transportation and Development officials said they continue to monitor the roads around the sinkhole to make sure they are structurally sound.
“DOTD, at this time, has no concerns related to the integrity of its state roads, specifically La. 70 in Assumption Parish,” DOTD spokeswoman Lauren Lee said.
Lee added DOTD engineers are watching elevation levels at four locations along La. 70 to make sure there are no changes.
“If conditions change, DOTD crews are prepared to close roads immediately to ensure public safety and will announce appropriate detours,” she said.
The 1-by-3-mile Napoleonville Dome salt formation was pushed up vertically from ancient sea beds and has been used for decades for brine production.
Caverns in the solid salt formation left by brine production often are used later to store natural gas, butane and other hydrocarbons. Brine, meanwhile, has several industrial process uses.